Zhdanov enlisted with the Russian Social Democratic Labour Party (Bolshevik) in 1915 and was promoted through the party ranks, becoming the All-Union Communist Party manager in Leningrad after the assassination of Sergei Kirov in 1934. He was Chairman of the RSFSR Supreme Soviet from 20 July 1938–20 June 1947. Though somewhat less active than Vyacheslav Molotov, Joseph Stalin, Lazar Kaganovich and Kliment Voroshilov, Zhdanov was a major perpetrator of the Great Terror and personally approved 176 documented execution lists.
In June 1940, he was sent to Estonia to supervise the establishment of the Estonian Soviet Socialist Republic and its annexation by the USSR. He was one of those accused during the U.S. House of Representatives' 1953-54 Kersten Committee investigation into the annexation of the Baltic States.
Zhdanov took a leading role during the Siege of Leningrad during World War II. After the cease-fire agreement between Finland and the USSR was signed in Moscow on 4 September 1944, Zhdanov directed the Allied Control Commission in Finland until the Paris peace treaty of 1947.
Zhdanov was appointed by Joseph Stalin to direct the Soviet Union's cultural policy in 1946. His first action (in December 1946) was to censor Russian writers such as Anna Akhmatova and Mikhail Zoshchenko. He formulated what became known as the Zhdanov Doctrine ("The only conflict that is possible in Soviet culture is the conflict between good and best"). During 1946–1947, Zhdanov was Chairman of the Soviet of the Union. In 1947, he organized the Cominform, designed to coordinate and control the communist parties around the world. In February 1948, he initiated purges among musicians, widely known as a struggle against formalism. Dmitri Shostakovich, Sergei Prokofiev, Aram Khachaturian and many other composers were reprimanded during this period. In June 1948, Stalin sent Zhdanov to the Cominform meeting in Bucharest. The purpose of the meeting was to condemn Yugoslavia, but Zhdanov took a more restrained line, in contrast to his co-delegate and rival Georgy Malenkov. This infuriated Stalin, who removed Zhdanov from all his posts and replaced him with Malenkov. Zhdanov was transferred to a sanatorium, where he died. It is possible that his death was the result of an intentional misdiagnosis.
Zhdanov died on 31 August 1948 in Moscow of heart failure; Nikita Khrushchev recalled in Khrushchev Remembers that Zhdanov was an alcoholic, and that during his "last days," Stalin would shout at him to stop drinking and insist that he drink only fruit juice. Stalin had talked of Zhdanov being his successor but Zhdanov's ill health gave his rivals, Lavrentiy Beria and Georgy Malenkov, an opportunity to undermine him.
Originating in 1946 and lasting until the late 1950s, Zhdanov's ideological code, known as the Zhdanov doctrine, Zhdanovism or zhdanovshchina, defined cultural production in the Soviet Union. Zhdanov intended to create a new philosophy of artistic creation valid for the entire world. His method reduced all of culture to a sort of chart, wherein a given symbol corresponded to a simple moral value. Zhdanov and his associates further sought to eliminate foreign influence from Soviet art, proclaiming that "incorrect art" was an ideological diversion. This doctrine suggested that the world was split into two opposing camps, namely, the “imperialistic”-led by the United States and the “democratic”-led by the Soviet Union, using Cold War terminology that also began in 1946. The one sentence that came to define Zhdanovshchina was “The only conflict that is possible in Soviet culture is the conflict between good and best". This cultural policy became strictly enforced, censoring writers, artists, and the intelligentsia, with punishment being applied for failing to conform to what was considered acceptable by Zhdanov’s standards. This policy officially ended in 1952, seen as having a negative impact on culture within the USSR. The origins of this policy can be seen before 1946 when critics proposed (wrongly according to Zhdanov) that Russian classics had been influenced by famous foreign writers, but the policy came into effect specifically to target “apolitical, ‘bourgeois’, individualistic works of the satirist Mikhail Zoshchenko and the poet Anna Akhmatova”, respectively writing for the literary magazines Zvezda and Leningrad. On 20 February 1948, Zhdanovshchina shifted its focus towards anti-formalism, targeting composers such as Dmitri Shostakovich. That April, many of the persecuted composers were pressed into repenting for displaying “formalism” in their music in a special congress of the Union of Soviet Composers. These composers were not rehabilitated by the Soviet Union until 28 May 1958.
Zhdanov was the most openly cultured of the leadership group and his treatment of artists was mild by Soviet standards of the time. He even wrote a satirical sketch ridiculing the attack on modernism.